---
title: "SMTP integration · RUAL Documentation"
description: "Use SMTP in RUAL blueprints. Send mail through any relay or submission host. Every block, with its pins. No backend code needed."
canonical: https://docs.rual.nl/integrations/smtp
language: en
---

# SMTP

Send mail through any relay or submission host.

> **Credentials** Create a [service provider](https://docs.rual.nl/blueprints/service-providers) for this service and point the blocks at it. The cluster holds the key, so it never sits on a pin or in a blueprint export.

## Blocks

Add these blocks on the canvas by searching for their name. Each block page lists its pins and how it behaves.

- [open connection `smtpconnection_open` Opens an SMTP connection to a relay or submission host. Nothing is sent until smtp send email runs; with verify on, the block dials the host once (EHLO, STARTTLS, AUTH, QUIT) so the flow can branch on success before composing a message.](https://docs.rual.nl/block-types/smtp/smtpconnection_open)

- [send email `smtpconnection_send_email` Builds an RFC 5322 message and hands it to the SMTP server on the connection. Use this to deliver through your own MTA (Exim, Postfix) rather than a hosted API.](https://docs.rual.nl/block-types/smtp/smtpconnection_send_email)

## Next steps

- [Third-Party Integrations](https://docs.rual.nl/tutorials/third-party-integrations): Calling outside APIs, receiving their webhooks, keeping data in sync and handling failures.

- [All integrations](https://docs.rual.nl/integrations): Everything RUAL connects to, by what it is for.